Wyoming mines the most uranium in the United States, producing approximately 238 million pounds of uranium concentrate (U3O8) since mines first started operating in 1951. Wyoming’s known reserves are estimated at 350 million pounds. Uranium is harnessed to produce nuclear energy.
Uranium is a naturally occurring heavy metal found in the Earth’s crust. It is one of the most common elements on Earth and has the highest atomic weight of all naturally occurring elements. Uranium was formed after a supernova approximately 6.6 billion years ago. It is almost as dense as gold and provides the primary heat source inside the Earth.
Atoms with the same number of protons but different numbers of neutrons are called isotopes. Uranium occurs predominantly as two isotopes, 238U and 235U. The most common isotope, 238U, comprises approximately 99.3% of natural uranium, while 235U accounts for about 0.7% of it.
235U, the rarer isotope, is the fissile isotope of uranium, meaning its nucleus can be split when bombarded with a neutron. This process releases a significant amount of energy and forms the basis of the controlled chain reaction that occurs in a nuclear power plant. This fissionability of uranium makes it an important fuel source for electricity and heat production worldwide.
Photo Credit: Uranium Energy Corp (UEC)
Wyoming has been a significant producer of uranium since the 1950s, when uranium exploration and development was spurred following World War II and with the announcement of President Eisenhower’s “Atoms for Peace” program in 1953. In total, Wyoming has produced upwards of 250 million pounds of yellowcake, a uranium concentrate powder that can be refined into nuclear fuel, maintaining its status as the largest producer in the United States.
In Wyoming, the majority of uranium deposits are found in sandstone formations as roll-front deposits. Roll-front deposits occur when uranium is mobilized in solution via surface water and/or groundwater movement through a host rock until it reaches a reducing environment where it falls out of solution and is concentrated.
In-Situ Recovery (ISR) is the primary uranium mining method used in Wyoming. ISR differs from conventional mining methods (underground and open pit) in that it doesn’t require extensive surface disturbance. This makes ISR far more economical for low-grade uranium deposits. This technique essentially reverses the process by which the uranium was originally deposited by introducing an oxidizing solution that remobilizes the uranium, which is then pumped to the surface for further processing into yellowcake. This means that the host formation remains structurally undisturbed.
Photo Credit: Uranium Energy Corp (UEC)
Uranium plays a crucial role in generating over 9% of the world’s electricity. It is harnessed to create nuclear energy, which is known for being a practical, reliable, and emissions-free power source—making it one of the most significant energy solutions globally. Concentrated deposits of uranium ore are found in sedimentary rocks across various regions in Wyoming, including the Powder River, Great Divide, Wind River, and Shirley Basins, along with the Little Mountain area in the northern Bighorn Range and the southeastern Greater Green River Basin.
Wyoming is the largest producer of uranium in the United States and holds its position as the nation’s leader in uranium reserves. This long history of exploration and production offers ample data and opportunities to boost production as the U.S. seeks to increase uranium production quickly.
Photo Credit: Courtesy of Wyoming Mining Association
Wyoming State Geological Survey
United States Department of Energy
United States Nuclear Regulatory Commission
Photo Credit: Courtesy of Wyoming Mining Association
